The London Assembly was facing an east-west split with the Tories retaining seats in the south and west of the capital on reduced majorities and Labour on course for thumping victories in the north and east.

Boris Johnson saw his “statutory” deputy mayor Richard Barnes booted out of the assembly after 12 years. He was ousted from Ealing and Hillingdon by Labour’s Onkar Sahota, an Ealing GP. Early Tory successes saw Richard Tracey hold Merton and Wandsworth and James Cleverly hold Bexley and Bromley. But wobbles started when Steve O’Connell’s Conservative majority in Croydon and Sutton was slashed from 42,665 to 9,418.

Labour wins included Len Duvall in Greenwich and Lewisham and Ken Livingstone’s prospective deputy mayor Val Shawcross in Lambeth and Southwark and it was set to claim the scalp of Tory Brian Coleman in Barnet and Camden.

The loss of Mr Barnes and prospect of defeat for Mr Coleman put Mr Johnson close to failing to get the nine assembly members he needs to prevent his budgets for City Hall and the Met being voted down. Insiders said Mr Barnes might have suffered a backlash over the feared closure of Ealing Hospital and the effect the HS2 train line may have on homes.